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Updated: Jun 26, 2026

Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing
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Benefits of Cardiac Resynchronization Therapy in an Asynchronous Heart Failure Model Induced by Left Bundle Branch Ablation and Rapid Pacing

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Baseline left bundle branch block with right bundle branch escape complexes in a patient with coronary artery

Arvind Bhimaraj1, Salaheldin Abusin, Bosko Margeta

  • 1Department of Medicine; John, H, Stroger Hospital of Cook County, Chicago, IL, USA. sayabusin@hotmail.com.

Cases Journal
|January 1, 2009
PubMed

Insights

Alternating bundle branch block (ABBB) is rare, especially with reperfusion therapy. Careful ECG analysis is crucial to distinguish true ABBB from conditions like high-grade AV block with escape beats mimicking ABBB.

Area of Science:

  • Cardiology
  • Electrophysiology
  • Medical Diagnostics

Background:

  • Alternating bundle branch block (ABBB) is an infrequent clinical finding, particularly with advancements in reperfusion therapy for acute myocardial infarction.
  • Electrocardiograms (ECGs) that mimic ABBB require meticulous interpretation to avoid misdiagnosis.

Purpose of the Study:

  • To present a case study of a complex ECG finding.
  • To highlight the importance of careful ECG analysis in differentiating true ABBB from simulated presentations.

Main Methods:

  • Case report presentation of a specific ECG.
  • Analysis of ECG characteristics, including baseline Left Bundle Branch Block (LBBB), high-grade Atrioventricular (AV) block, and escape complexes with Right Bundle Branch Block (RBBB) morphology.

Main Results:

  • The presented ECG demonstrated a baseline LBBB that evolved into a high-grade AV block.
  • Escape complexes exhibited RBBB morphology, creating a pattern that could be mistaken for ABBB.

Conclusions:

  • ECGs showing high-grade AV block with escape beats of RBBB morphology can be erroneously interpreted as ABBB.
  • Thorough ECG evaluation is essential to correctly identify the underlying rhythm and avoid misdiagnosis of ABBB.

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